Phil 220 Argument Types

Inductive argument

arguments that tend to render the conclusion likely or probably true on the basis of the premises.

Strong inductive argument

an inductive argument in which if the premises are true, they provide strong support for the conclusion, making it likely true.

weak inductive argument

an inductive argument where the premises fail to provide significant support for the conclusion, making its truth uncertain.

cogent inductive argument

the argument is both strong and the premises are true, if a premise is false then it is not cognet.

deductive arguments

intend to provide conclusive reasons for why a certain claim is true. if the premises are assumed to be true then it is impossible for the conclusion to be false. Truth preserving

are deductive arguments valid

yes because they guarantee a truth preserving

sound argument

one in which the argument is both valid and the premises are in fact true

enthymemes

an argument with an unstated or unassumed premise

Mathematics

Deductive

Definition

(Deductive) the conclusion is claimed to be true merely given the use of the terms in the premises.

Modus Ponens (affirming the antecedent)

(Deductive) the most basic argument that includes a conditional

1. If A then B

2. A

3. Thus B

1. John is a bachelor

2. Therefore John is an unmarried man

Definition

1. If Steve is actually Spiderman, then Steve likes to kiss orangatangs

2. Steve is actually spiderman

3. Therefore Steve likes to kiss orangatangs

Modus Ponens

Invalid of Modus Ponens (denying the antecedent)

1. If A than B

2. Not A

3. Thus not B

1. If Steve is actually Spiderman, then Steve likes to kiss orangatangs

2. Steve is not Spiderman

3. Therefore, steve does not like to kiss orangatangs

denying the antecedent

Modus Tollens

(Deductive) denying the consequent

1. If A than B

2. Not B

3. Thus not A

1. If i take shower, then I will get wet

2. I did not get wet

3. Thus, I did not take a shower

Modus Tollens

Invalid of Modus Tollens (affirming the consequent)

1. If A than B

2. B

3. Thus A

1. If i take a shower then I will get wet

2. I got wet

3. Thus, I took a shower

Invalid of Modus Tollens (affirming the consequent)

Hypothetical Syllogism

(deductive) consists of 2 premises and a conclusion, usually has two conditional statements

1. If A then B

2. If B then C

3. Thus if A, then C

1. If AU is worth the tuition it charges then it must require a semester of practical thinking for each of its students

2. If AU requires a semester of PC for each of its students then AU is an elite liberal arts college

3. Therefore AU is worth the tuition if charges then AU is an elite liberal arts college

Hypothetical Syllogism

Disjunctive Syllogism

(Deductive) an either or statement in one of its premises

1. Either A or B

2. Not A

3. Thus B

1. Either trump is a penguin or my nephew is a flatulent

2. trump is not a penguin

3. therefore my nephew is a flatulent

Disjunctive Syllogism

Categorical Syllogism

(Deductive) when each premises contain either a universal proposition all or none and or a particular some proposition

1. All A are B

2. All B are C

3. Thus all A are C

1. All presidents are humans

2. all humans have brains

3. therefore all presidents have brains

Categorical Syllogism

Predictions

(Inductive) arguments that move from some kind of knowledge of some event or events in the past to claim about the future

1. The stock BLRB has increased in value over 30% over the past 6 months

2. therefore the BLRB stock will probably increase 5%next month

Prediction

Analogy

(Inductive) arguments make a case for the conclusion based on on a relationship that can be determined between or among the properties or features of various things or events

1. machines are produced by intelligent designs

2. many natural parts of the universe resemble machines

3. therefore probably the universe (or at least many parts of its natural designs) was produced by intelligent design

Analogy

Enumerative (generalizations)

(Inductive) argument that proceeds from knowledge of a selected sample, to some general claim (usually about a whole group but not always)

1. The last 20 lottery tickets I bought were losers

2. therefore the next lottery ticket I buy will probably be a loser

enumerative

1. ¾ of college students have an active twitter account

2. Thus, most adults probably have ana active twitter account

enumerative

statistical

also inductive because they are not exact but rather generializations

1. The dallas cowboys are given 7 to 2 odds of winning the NFC championship

2. the buffalo bills are given an 8 to 3 odds of winning the AFC championship

3. therefore, the cowboys and the bills will meet in the superbowl

Statistical (inductive)

Casual

(Inductive) an argument that has a casual statement as a conclusion, it attempts to demonstrate a signifigant kind of relationship that holds among events

1. everytime I turn off my phone, i pass out and wake up under the stairs of the student center

2. thus, turning my phone off is the cause of that weird phenomena

casual

Authority

(inductive) arguments that draw conclusions from the testimony of, or appeal to, authority, experts, or other commonly respected or revealed individuals

1. Steve Hawking tells us fermions have no mass

2. therefore probably fermions have no mass

authority

antecedent

“if” part of an argument

consequent

“then” part of an argument